Question

find the area of the quadrilateral 2cm 4cm 12cm 8cm​

Answer 1

Answer:

In quadrilateral ABCD, 

AB=3 cm,BC=4 cm,CD=2 cm,DA=5 cm and ∠ABC=900

Area of ABCD = Area of ΔABC+ Area of ΔACD

In ΔABC,∠B=900

∴  Area of ΔABC = 21×AB×BC=21×3×4 cm2=6cm2

In ΔABC, applying pythagorous theorem we get,

AC2=AB2+BC2

⇒AC2=32+42

⇒AC2=9+16

⇒AC2=25

⇒AC=5

∴AC=5 cm

In ΔACD, semi-perimeter s=22+5+5cm=6 cm

Applying Heron's formula,

Area of Δ ACD = S(S−a)(S−b)(S−c)

Answer 2

Step-by-step explanation:

Formula =Area of General Quadrilateral Formula = 1/2 x diagonals length x ( sum of the height of two triangles

Using this formula

Let's see

1/2*12 cm*(2+4+8)cm

6cm*14cm

20 sq.cm